The squeeze cast process parameters of AZ80 magnesium alloy were optimized by morphological matrix. Experiments were conducted by varying squeeze pressure, die pre-heat temperature and pressure duration using L9（33）...The squeeze cast process parameters of AZ80 magnesium alloy were optimized by morphological matrix. Experiments were conducted by varying squeeze pressure, die pre-heat temperature and pressure duration using L9（33） orthogonal array of Taguchi method. In Taguchi method, a 3-level orthogonal array was used to determine the signal/noise ratio. Analysis of variance was used to determine the most significant process parameters affecting the mechanical properties. Mechanical properties such as ultimate tensile strength, elongation and hardness of the components were ascertained using multi variable linear regression analysis. Optimal squeeze cast process parameters were obtained.展开更多
AZ91D alloy composites with1.0%CNTs have been fabricated by a method combined ball milling with stirring casting.The composite was investigated using optical microscopy(OM),X-ray diffraction(XRD),Fourier transform inf...AZ91D alloy composites with1.0%CNTs have been fabricated by a method combined ball milling with stirring casting.The composite was investigated using optical microscopy(OM),X-ray diffraction(XRD),Fourier transform infrared spectroscope(FT-IR),scanning electron microscope(SEM),transmission electron microscope(TEM)and room temperature(RT)tensile test.Theresults show that CNTs were homogeneously distributed in the matrix and maintained integrated structure.The yield strength andductility of AZ91D/CNTs composite were improved by47.2%and112.2%,respectively,when compared with the AZ91alloy.Theuniform distribution of CNTs and the strong interfacial bonds between CNT and the matrix are dominated to the simultaneousimprovement of yield strength and ductility of the composite.In addition,the grain refinement as well as the finerβphase(Mg17Al12)with homogenous distribution in the matrix can also slightly assist to the enhancement of the mechanical properties of thecomposite.展开更多
A356 aluminum alloys reinforced with carbon nano-tubes (CNTs) were produced by stir casting and compocasting routes and their microstructural characteristics and hardness were examined.In order to alleviate the proble...A356 aluminum alloys reinforced with carbon nano-tubes (CNTs) were produced by stir casting and compocasting routes and their microstructural characteristics and hardness were examined.In order to alleviate the problems associated with poor wettability, agglomeration and gravity segregation of CNTs in the melt, CNTs were introduced into the melts by injection of CNT deposited aluminum particles instead of raw CNTs.Aluminum particles with mean diameters of less than 100 μm were first deposited by CNTs using Ni-P electroless plating technique and then injected into the melt agitated by a mechanical stirrer.The slurry was subsequently cast at temperatures corresponding to full liquid as well as 0.15 and 0.30 solid fractions.The results show that addition of CNTs to A356 matrix can significantly refine both full liquid and semi-solid cast microstructures.Hardness of the samples is also significantly increased by addition of CNTs and A356-CNT composite cast at 0.3 solid fraction produces the highest hardness.展开更多
基金Project (50975263) supported by the National Natural Science Foundation of ChinaProject (2011DFA50520) supported by International Science Technology Cooperation Program of China
文摘The squeeze cast process parameters of AZ80 magnesium alloy were optimized by morphological matrix. Experiments were conducted by varying squeeze pressure, die pre-heat temperature and pressure duration using L9（33） orthogonal array of Taguchi method. In Taguchi method, a 3-level orthogonal array was used to determine the signal/noise ratio. Analysis of variance was used to determine the most significant process parameters affecting the mechanical properties. Mechanical properties such as ultimate tensile strength, elongation and hardness of the components were ascertained using multi variable linear regression analysis. Optimal squeeze cast process parameters were obtained.
基金Project(51464034) supported by the National Natural Science Foundation of ChinaProjects(GJJ151309,GJJ151010) supported by the Education Department of Jiangxi Province,China
文摘AZ91D alloy composites with1.0%CNTs have been fabricated by a method combined ball milling with stirring casting.The composite was investigated using optical microscopy(OM),X-ray diffraction(XRD),Fourier transform infrared spectroscope(FT-IR),scanning electron microscope(SEM),transmission electron microscope(TEM)and room temperature(RT)tensile test.Theresults show that CNTs were homogeneously distributed in the matrix and maintained integrated structure.The yield strength andductility of AZ91D/CNTs composite were improved by47.2%and112.2%,respectively,when compared with the AZ91alloy.Theuniform distribution of CNTs and the strong interfacial bonds between CNT and the matrix are dominated to the simultaneousimprovement of yield strength and ductility of the composite.In addition,the grain refinement as well as the finerβphase(Mg17Al12)with homogenous distribution in the matrix can also slightly assist to the enhancement of the mechanical properties of thecomposite.
文摘A356 aluminum alloys reinforced with carbon nano-tubes (CNTs) were produced by stir casting and compocasting routes and their microstructural characteristics and hardness were examined.In order to alleviate the problems associated with poor wettability, agglomeration and gravity segregation of CNTs in the melt, CNTs were introduced into the melts by injection of CNT deposited aluminum particles instead of raw CNTs.Aluminum particles with mean diameters of less than 100 μm were first deposited by CNTs using Ni-P electroless plating technique and then injected into the melt agitated by a mechanical stirrer.The slurry was subsequently cast at temperatures corresponding to full liquid as well as 0.15 and 0.30 solid fractions.The results show that addition of CNTs to A356 matrix can significantly refine both full liquid and semi-solid cast microstructures.Hardness of the samples is also significantly increased by addition of CNTs and A356-CNT composite cast at 0.3 solid fraction produces the highest hardness.
